#include <bits/stdc++.h>
using namespace std;

#define int int64_t

using PII = pair<int, int>;
using TII = tuple<int, int, int>;
template<class T> using V = vector<T>;
using i64 = long long;
using i128 = __int128;
using u64 = unsigned long long;

#define FOR(i, a, b) for (int i = (int)(a); i <= (int)(b); i++)
#define FOR2(i, a, b, c) for (int i = (int)(a); i <= (int)(b); i += c)
#define FORD(i, b, a) for (int i = (int)(a); i >= (int)(b); i--)
#define FORD2(i, b, a, c) for (int i = (int)(a); i >= (int)(b); i -= c)
#define ALL(a) a.begin(), a.end()
#define RALL(a) a.rbegin(), a.rend()
#define lowbit(x) ((x) & (-x))
#define RE return;
#define Yes cout << "Yes" << endl;
#define YES cout << "YES" << endl;
#define No cout << "No" << endl;
#define NO cout << "NO" << endl;
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define sz(x) (int)(x).size()

void solve() {
    int n;
    cin >> n;

    int mx = 1e9;

    int x1 = -mx, y1 = -mx, x2 = -mx, y2 = mx;

    V<array<int, 2>> w(n + 1);

    FOR(i, 1, n) cin >> w[i][0] >> w[i][1];

    int mn1 = 1e18, mn2 = 1e18;

    FOR(i, 1, n) {
        mn1 = min(mn1, w[i][0] + w[i][1]);
        mn2 = min(mn2, w[i][0] - w[i][1]);
    }

    int dis;
    cout << "? D " << mx << endl;
    cin >> dis;
    cout << "? D " << mx << endl;
    cin >> dis;
    cout << "? L " << mx << endl;
    cin >> dis;
    cout << "? L " << mx << endl;
    cin >> dis;

    int del1 = mn1 + 4 * mx - dis;

    cout << "? U " << mx << endl;
    cin >> dis;
    cout << "? U " << mx << endl;
    cin >> dis;
    cout << "? U " << mx << endl;
    cin >> dis;
    cout << "? U " << mx << endl;
    cin >> dis;
    int del2 = mn2 + 4 * mx - dis;

    int x = (del1 + del2) / 2;

    int y = del1 - x;

    cout << "! " << x << ' ' << y << endl;
}

signed main() {
    int Task = 1;

    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cin >> Task;
    while (Task--) {
        solve();
    }

    return 0;
}
